The Baghdad Battery
200 CE
The Accidental Circuit
Sometimes, the future is buried in the past. In 1936, workers digging near Khujut Rabu, Iraq, found a small, 14cm clay pot. It looked like garbage. But inside, it held a specific arrangement of metals that looked suspiciously like engineering.
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Sometimes, the future is buried in the past. In 1936, workers digging near Khujut Rabu, Iraq, found a small, 14cm clay pot. It looked like garbage. But inside, it held a specific arrangement of metals that looked suspiciously like engineering.
A rolled copper sheet formed a tube (the cathode — the positive end). An iron rod was suspended inside it (the anode — the negative end), held in place by an asphalt stopper so it never touched the copper. This is not a random arrangement; in modern physics, this is a simple battery — a galvanic cell made from different metals and an acid. Pour an electrolyte like vinegar or lemon juice into the jar, and the laws of chemistry take over. Electrons flow from the iron to the copper. The jar produces 0.5 to 1.1 volts.